Expandable section mill and method

ABSTRACT

An expandable section mill includes a body, a piston movably disposed within an inner cavity of the body, the piston including a wedge surface, a jaw member pivotally connected to a lower end of the body, and a blade assembly affixed to a tapered surface of the jaw member. The jaw member includes an internal channel system for fluid flow through the jaw member to one or more outlets on the jaw member. The jaw member includes a pivot surface. The wedge surface of the piston engages the pivot surface of the jaw member to pivot the jaw member between a retracted position and an extended position. In the retracted position, the blade assembly is positioned radially inward relative to an outer surface of the body. In the extended position, the blade assembly extends radially outward relative to the outer surface of the body.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent application Ser. No. 14/536,846, filed on Nov. 10, 2014, which is incorporated herein by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an expandable section mill in a retracted position.

FIG. 2 is a side view of the expandable section mill in an extended position.

FIG. 3 is a cross-sectional view of the expandable section mill in the retracted position.

FIG. 4 is a perspective cross-sectional view of the expandable section mill in the extended position.

FIG. 5 is a schematic view of the expandable section mill showing an internal channel system of a first jaw member.

FIG. 6 is a schematic view of the expandable section mill showing an internal channel system of a second jaw member.

FIG. 7 is an exploded perspective view of the expandable section mill in the extended position.

FIG. 8 is a bottom view of the expandable section mill in the extended position.

FIG. 9 is a bottom view of an alternate embodiment of the expandable section mill in the extended position.

FIG. 10 is a schematic view of the alternate embodiment of the expandable section mill in the extended position in contact with a cement layer between concentric tubular members.

FIG. 11 is a schematic view of the expandable section mill in the extended position cutting a larger tubular member below a smaller tubular member.

FIG. 12 is a cross-sectional view of an alternate expandable section mill in a retracted position.

FIG. 13 is a perspective view of a piston of the expandable section mill of FIG. 12.

FIG. 14 is a perspective view of a jaw member of the expandable section mill of FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate expandable section mill 10, which may include top sub 12 operatively connected to body 14. First jaw member 16 and second jaw member 18 may be pivotally attached to body 14, such as by hinge pin 20. Blade assembly 22 may be affixed to tapered surface 24 of first jaw member 16. Blade assembly 26 may be affixed to tapered surface 28 of second jaw member 18. First and second jaw members 16 and 18 may be selectively pivoted between a retracted position shown in FIG. 1 and an extended position shown in FIG. 2. With jaw members 16 and 18 in the retracted position, expandable section mill 10 may be lowered into a casing or other tubular member in a wellbore. When blades 22 and 26 reach a desired depth, jaw members 16 and 18 may be pivoted into the extended position for cutting or sectioning a portion of the casing or other tubular member in which the jaw members 16 and 18 are disposed. In an alternate embodiment, expandable section mill 10 may include first jaw member 16 only.

Referring now to FIGS. 3 and 4, piston 30 may be disposed within inner cavity 32 of body 14. Internal channel 34 may extend through top sub 12, and may be in fluid communication with inner cavity 32 of body 14. Guide bolt 36 may cooperate with slot 37 of piston 30 to prevent piston 30 from rotating within inner cavity 32 of body 14. First jaw member 16 may be pivoted into the extended position by increasing the pressure of a fluid flowing through internal channel 34 of top sub 12. As the fluid pressure increases, piston 30 is pushed downward within inner cavity 32. As piston 30 moves downward, its lower end 38 may engage pivot surface 40 on the upper end of first jaw member 16 such that first jaw member 16 is pivoted into the extended position shown in FIG. 4. The downward force applied by piston 30 may pivot tapered surface 24 of first jaw member 16 outward. In this position, piston 30 may be supported by shoulder 42 of piston 30 engaging shoulder 44 of body 14. Shoulders 41 and 42 may have reciprocal shapes.

Piston 30 and jaw members 16 and 18 may include internal channels or fluid paths that allow fluid flowing through internal channel 34 and inner cavity 32 of body 14 to flow through piston 30 and jaw members 16 and 18 to assist in the cutting or sectioning process. Referring to FIGS. 3 and 4, piston 30 may include first piston channel 46, which may be in fluid communication with proximal channel 48 of first jaw member 16 when first jaw member 16 is in the extended position. Hinge pin 20 may include channel 49 interconnecting segments of proximal channel 48 of first jaw member 16. Proximal channel 48 may lead to outlet 50 on rear surface 51 of first jaw member 16. First piston channel 46 may also be in fluid communication with a proximal channel of second jaw member 18 (not shown), which may direct fluid to an outlet on a rear surface of second jaw member 18.

Expandable section mill 10 may further include one or more seals for preventing leaks of the fluid flowing through top sub 12 and body 14. As shown in FIG. 3, expandable section mill 10 may include top sub seal 52 between an inner surface of body 14 and an outer surface of top sub 12. Piston seal 53 may be positioned between an inner surface of body 14 and an outer surface of piston 30. Guide bolt seal 54 may be disposed around an outer surface of guide bolt 36 to prevent leaks of fluid flowing through inner cavity 32 through any spaces surrounding guide bolt 36. Top sub seal 52, piston seal 53, and guide bolt seal 54 may be an O-ring or any other seal means known in the art.

Referring now to FIG. 5, piston 30 may also include second piston channel 55 in fluid communication with distal channel system 56 of first jaw member 16 when first jaw member 16 is in the extended position. Distal channel system 56 may lead to outlet 57 at lower end 58 of first jaw member 16.

FIG. 6 shows that piston 30 may further include third piston channel 59 in fluid communication with distal channel system 60 of second jaw member 18 when second jaw member 18 is in the extended position. Distal channel system 60 may lead to outlet 61 at lower end 62 of second jaw member 18.

With reference now to FIG. 7, distal channel system 56 of first jaw member 16 (shown in FIG. 5) may also extend to one or more rear outlets 64 on rear surface 51 of first jaw member 16. Distal channel system 56 may also extend to one or more cutting outlets 66 on tapered surface 24. Tapered surface 24 of first jaw member 16 may also include blade assembly recess 68 dimensioned to receive blade assembly 22. Blade assembly 22 may include one or more cutting members 70 affixed to blade support 72, which may be placed into blade assembly recess 68 and fastened to first jaw member 16 with one or more bolts 74 (shown in FIG. 5). Tapered surface 24 of first jaw member 16 may further include wear insert recess 76 dimensioned to receive wear insert 78. Wear insert recess 76 may be located below blade assembly recess 68. Wear insert 78 may be placed into wear insert recess 76 and fastened to first jaw member 16 with bolts or screws through apertures 80 in first jaw member 16 (shown in FIG. 3). Outer surface 82 of wear insert 78 may have a curvature matching that of tapered surface 24 of first jaw member 16. Outer surface 82 of wear insert 78 may also protrude radially outward from tapered surface 24 when wear insert 78 is secured in wear insert recess 76. In this way, wear insert 78 may prevent wear on tapered surface 24 of first jaw member 16. Second jaw member 18 may also include a blade assembly recess (not shown), blade assembly 26, a wear insert recess 83, and wear insert 78, each having the features described above in connection with first jaw member 16. Blade assembly 26 of second jaw member 18 may include one or more cutting members 86 affixed to blade support 88. Blade support 72 and 88 may be formed of steel or any other durable material. Cutting members 70 and 86 may be formed of a metal such as carbide or any other material capable of cutting into steel.

FIG. 8 shows a bottom view of expandable section mill 10. In the extended position, as shown, blade assembly 22 of first jaw member 16 and blade assembly 26 of second jaw member 18 may extend radially outward relative to outer surface 84 of body 14. Rotation of expandable section mill 10 may cause first and second jaw members 16 and 18 to push against one another, thereby reducing the force on hinge pin 20. Rotation in the indicated direction may also cause cutting members 70 and 86 to cut into an inner wall of a tubular member in which expandable section mill 10 is disposed (e.g., a casing in a wellbore).

FIG. 9 shows a bottom view of an alternate embodiment of expandable section mill 10 in the extended position. In this embodiment, scraper blade assembly 92 is positioned in blade assembly recess 68 of first jaw member 16 (shown in FIG. 7) and scraper blade assembly 94 is positioned in a blade assembly recess of second jaw member 18. In this way, scraper blade assemblies 92 and 94 replace blade assemblies 22 and 26, respectively. Scraper blade assemblies 92 and 94 may have different shapes and be formed of different material than blade assemblies 22 and 26. For example, scraper blade assemblies 92 and 94 may be formed of steel or any other material capable of scraping/removing cement from a casing or inner surface of a pipe. Scraper blade assemblies 92 and 94 may or may not include separate cutting members. In the extended position of this embodiment, as shown in FIG. 9, scraper blade assemblies 92 and 94 may extend radially outward relative to outer surface 84 of body 14. Rotation of this embodiment of expandable section mill 10 may cause scraper blade assemblies 92 and 94 to cut into an inner wall of a tubular member. Scraper blade assemblies 92 and 94 may be designed to cut into, break apart, or remove cement, such as but not limited to cement disposed in an annulus between concentric casings set in a wellbore.

With reference again to FIGS. 1 and 2, expandable section mill 10 may be lowered into casing 100 with first and second jaw members 16 and 18 in the retracted position (shown in FIG. 1). In the retracted position, blade assemblies 22 and 26 are held away from inner surface 102 of casing 100 and radially inward relative to the outer surface of body 14. Suitable methods of lowering expandable section mill 10 include, but are not limited to, attaching top sub 12 to a lower end of a tubular string, such as a work string or coiled tubing. When jaw members 16 and 18 reach a desired depth within casing 100, piston 30 may be lowered within body 14 in order to pivot jaw members 16 and 18 into the extended position (shown in FIG. 2). In the extended position, each blade assembly 22 and 26 may engage inner surface 102 of casing 100. Rotation of expandable section mill 10 will cause cutting members 70 and 86 of blade assemblies 22 and 26 to begin cutting into inner surface 102.

Over time, the outer surfaces of wear inserts 78 of first and second jaw members 16 and 18 may engage inner surface 102 of casing 100 below the cut or sectioned portion as shown in FIG. 2. In this way, the width of cutting members 70 and 86 of blade assemblies 22 and 26 may determine the radial extent to which expandable section mill 10 cuts into casing 100. The contact between wear inserts 78 and inner surface 102 of casing 100 may allow expandable section mill 10 to be lowered further during cutting operations to control the length of the window cut by blade assemblies 22 and 26. In this way, wear inserts 78 may stabilize expandable section mill 10 during cutting operations. After the desired window is cut in casing 100, fluid flow through internal channel 34 may be discontinued or reduced and expandable section mill 10 may be lifted from casing 100. When the tapered upper ends of blade assemblies 22 and 26 engage casing 100 above the window, the tapered upper ends may assist in pivoting jaw members 16 and 18 into the retracted position. Expandable section mill may be removed from casing 100 in the retracted position. In this way, expandable section mill 10 may be used to cut or section a window or other opening in a casing or other tubular member.

Casing 100 may be disposed in a wellbore with one or more other casings concentrically arranged and separated by cement in each annular space. For example, FIG. 10 shows casing 100 disposed within second casing 104, which is disposed within third casing 106. In this example, casing 100 has a smaller inner diameter than second casing 104, which has a smaller inner diameter than third casing 106. Cement layer 108 may be disposed between casing 100 and second casing 104, and cement layer 109 may be disposed between second casing 104 and third casing 106. In order to cut a section or window in second casing 104, a portion of cement layer 108 must be removed or broken up (after a window is cut from casing 100). Expandable section mill 10 may be fitted with scraper blade assemblies 92 and 94 on first and second jaw member 16 and 18, and lowered in the retracted position into casing/cement assembly. When jaw members 16 and 18 reach the depth of the window cut from casing 100, jaw members 16 and 18 may be pivoted into the extended position so that each scraper blade assembly 92 and 94 may engage an inner surface of cement layer 108. Rotation of expandable section mill 10 will cause scraper blade assemblies 92 and 94 to break apart or remove cement layer 108. This operation may be conducted with or without wear inserts 78 attached within the wear insert recesses of first and second jaw members 16 and 18. If included, wear inserts 78 may be used to stabilize jaw members 16 and 18 during rotation through contact between wear inserts 78 and the inner surface of cement layer 108 below scraper blade assemblies 92 and 94. This contact between wear inserts 78 and the inner surface of cement layer 108 may not occur, however, if the thickness of cement layer 108 is less than the width of scraper blade assemblies 92 and 94. Once the desired portion of cement layer 108 is removed or broken apart, jaw members 16 and 18 may be pivoted into the retracted position in order to remove expandable section mill 10 from the wellbore. In this way, expandable section mill 10 may be used to remove or break apart a cement layer disposed between two concentrically arranged tubular members. This embodiment of expandable section mill 10 may also be used to remove cement disposed along an inner wall of any tubular member.

Expandable section mill 10 may be used with jaw members of varying lengths to accomplish cutting or sectioning of casing or other tubular members having varying internal diameters. Referring now to FIG. 11, third jaw member 110 and fourth jaw member 112 may be attached to expandable section mill 10. Third and fourth jaw members 110 and 112 may have the same features as first and second jaw members 16 and 18 described above, except that third and fourth jaw members 110 and 112 may be longer. Specifically, third and fourth jaw members 110 and 112 may include a longer straight portion above tapered surfaces 114 and 116 to which blade assemblies 118 and 120 are attached. By spacing blade assemblies 118 and 120 a greater distance from hinge pin 20, third and fourth jaw members 110 and 112 are able to cut or section a casing or other tubular member having a larger internal diameter when jaw members 110 and 112 are pivoted into the extended position. In an alternate embodiment, the scraper blade assemblies may be affixed to third and fourth jaw members 110 and 112 in the same way that they are affixed to first and second jaw members 16 and 18. Expandable section mill 10 fitted with third and fourth jaw members 110 and 112 and the scraper blade assemblies may be used to remove cement layer 108 in the same manner as shown and described in connection with FIG. 10.

As shown in FIG. 11, expandable section mill 10 fitted with third and fourth jaw members 110 and 112 may be lowered through a tubular member having a smaller inner diameter to reach and cut or section a lower tubular having a larger inner diameter. Specifically, expandable section mill 10 may be lowered through casing 100 with jaw members 110 and 112 in the retracted position. When jaw members 110 and 112 reach the window cut in casing 100 and the removed section of cement layer 108, jaw members 110 and 112 may be pivoted into the extended position. Rotation of expandable section mill 10 by rotating top sub 12 may cause blade assemblies 118 and 120 to cut into inner surface 126 of second casing 104. In this way, expandable section mill 10 may be lowered through a first tubular member having a smaller inner diameter to reach a second tubular member having a larger inner diameter, in order to cut or section a window or other opening in the second tubular member. The procedure set forth in connection with FIGS. 10 and 11 may be used to remove a portion of cement layer 109 and to cut a window in third casing 106 if necessary.

FIG. 12 illustrates an alternate embodiment of the expandable section mill. Expandable section mill 130 may include top sub 132 operatively connected to body 134. Jaw member 136 may be pivotally attached to body 134, such as with hinge pin 138. Blade assembly 140 may be affixed to tapered surface 142 of jaw member 136. Expandable section mill 130 may also include a second jaw member as described above in connection with expandable section mill 10. Expandable section mill 130 may further include piston 144 disposed within inner cavity 146 of body 134. Internal channel 148 may extend through top sub 132, and may be in fluid communication with inner cavity 146 of body 134.

Referring now to FIG. 13, lower section 150 of piston 144 may include a double wedge shape. Specifically, lower section 150 may include first wedge surface 152 and first wing extension 154 configured to engage jaw member 136. Lower section 150 may also include second wedge surface 156 and second wing extension 158 configured to engage a second jaw member. Piston 144 may further include first piston channel 160, second piston channel 162, and third piston channel 164. Jaw member 136 shown in FIG. 14 may include blade assembly recess 166 and wear insert recess 168 on tapered surface 142.

With reference again to FIG. 12, jaw member 136 may be pivoted into an extended position by increasing the pressure of a fluid flowing through internal channel 148 of top sub 132. As the fluid pressure increases, piston 144 is pushed downward within inner cavity 146 such that first wedge surface 152 engages pivot surface 170 of jaw member 136. As piston 144 continues its downward movement, first wedge surface 152 may slide along pivot surface 170 of jaw member 136 thereby pivoting jaw member 136 into an extended position in which blade assembly 140 extends radially beyond outer surface 172 of body 134. The downward movement of piston 144 may also pivot a second jaw member into an extended position through second wedge surface 156 engaging with and sliding along a pivot surface of the second jaw member. First and second wedge surfaces 152 and 156 may increase the leverage applied by piston 144 on jaw member 136 and a second jaw member, respectively.

First wing extension 154 of piston 144 may engage and slide along side surface 173 of jaw member 136 (shown in FIG. 14). In the retracted and the extended positions of jaw member 136, contact between first wing extension 154 of piston 144 and side surface 173 of jaw member 136 may prevent piston 144 from rotating relative to jaw member 136. Additionally, second wing extension 158 may engage a side surface of a second jaw member to prevent piston 144 from rotating relative to the second jaw member. In this way, first and second wing extensions 154 and 158 maintain alignment of piston 144 with jaw member 136 and a second jaw member.

With reference again to FIG. 12, first piston channel 160 may be in fluid communication with proximal channel 174 of jaw member 136 in the extended position. Hinge pin 138 may include channel 176 interconnecting segments of proximal channel 174 of jaw member 136. Proximal channel 174 may lead to outlet 178 on rear surface 180 of jaw member 136. First piston channel 160 may also be in fluid communication with a proximal channel of a second jaw member, which may direct fluid to an outlet on a rear surface of the second jaw member.

Also in the extended position, second piston channel 162 may be in fluid communication with a distal channel system of jaw member 136 that extends from inlet 182 on pivot surface 170 to outlet 184 at lower end 186 of jaw member 136 (shown in FIG. 14). Second piston channel 162 and the distal channel system of jaw member 136 may direct fluid flow through jaw member 136 to outlet 184 at lower end 186. Similarly, third piston channel 164 may be in fluid communication with a distal channel system of a second jaw member, which may direct fluid flow through the second jaw member to an outlet at its lower end.

Referring again to FIG. 12, expandable section mill 130 may further include one or more seals for preventing leaks of the fluid flowing through top sub 132 and body 134. Expandable section mill 130 may include top sub seal 188 between an inner surface of body 134 and an outer surface of top sub 132. Piston seal 190 may be positioned between an inner surface of body 134 and an outer surface of piston 144. Each seal may be formed of an O-ring or any other suitable seal means.

Except as otherwise noted, expandable section mill 130 includes the same features and functions in the same way as expandable section mill 10. Expandable section mill 130 may be used to cut or section a window or other opening in a casing or other tubular member as described above in connection with expandable section mill 10. Specifically, rotation of expandable section mill 130 with jaw member 136 and a second jaw member in the extended position may cause blade assembly 140 and a blade assembly of the second jaw member to cut into an inner wall of a tubular member in which expandable section mill 130 is disposed (e.g., a casing in a wellbore) in the same way described above in connection with expandable section mill 10. Also, a scraper blade assembly (instead of blade assembly 140) may be positioned in blade assembly recess 166 of jaw member 136.

While preferred embodiments have been described, it is to be understood that the embodiments are illustrative only and that the scope of the invention is to be defined solely by the appended claims when accorded a full range of equivalents, many variations and modifications naturally occurring to those skilled in the art from a review hereof. 

1. An expandable section mill comprising: a body having an outer surface and an inner cavity; a piston disposed within the inner cavity of the body, a lower section of the piston including a wedge surface; a jaw member pivotally connected to a lower end of the body, the jaw member including a tapered surface, an internal channel system for fluid flow through the jaw member, and a pivot surface at an upper end of the jaw member, wherein the pivot surface is configured to engage the wedge surface of the piston; a blade assembly affixed to the tapered surface of the jaw member, wherein the tapered surface includes a wear surface below the blade assembly.
 2. The expandable section mill of claim 1, wherein the piston is moveable within the inner cavity for pivoting the jaw member between a retracted position, in which the blade assembly is positioned radially inward relative to the outer surface of the body, and an extended position, in which the blade assembly extends radially outward relative to the outer surface of the body, when the wedge surface of the piston engages the pivot surface of the jaw member.
 3. The expandable section mill of claim 2, wherein the piston further includes a wing extension adjacent to the wedge surface, and wherein the wing extension is configured to engage a side surface of the jaw member for aligning the piston with the jaw member.
 4. The expandable section mill of claim 2, wherein the wear surface is formed by a wear insert affixed within a recess on the tapered surface of the jaw member, wherein an outer surface of the wear insert has a curvature that matches a curvature of the tapered surface.
 5. The expandable section mill of claim 2, wherein the blade assembly comprises a cutting member affixed to a blade support, and wherein the blade support is affixed to a recess on the tapered surface of the jaw member.
 6. The expandable section mill of claim 5, wherein the internal channel system includes an outlet on the tapered surface adjacent to the cutting member of the blade assembly for fluid flow through the jaw member to the cutting member of the blade assembly.
 7. The expandable section mill of claim 6, wherein the internal channel system includes an outlet on a lower end of the jaw member and an outlet on a rear surface of the jaw member for fluid flow through the jaw member to the lower end and the rear surface thereof.
 8. The expandable section mill of claim 2, wherein the piston includes a first internal channel in fluid communication with the internal channel system of the jaw member for fluid flow through the piston and the jaw member when the jaw member is in the extended position.
 9. The expandable section mill of claim 8, wherein the piston further includes a second internal channel, and the jaw member further includes a proximal internal channel extending to an outlet on a rear surface of the jaw member; and wherein the second internal channel of the piston is in fluid communication with the proximal internal channel of the jaw member for fluid flow through the piston and the jaw member to the rear surface thereof when the jaw member is in the extended position.
 10. The expandable section mill of claim 9, wherein the jaw member is pivotally connected to the body with a hinge pin, wherein the hinge pin includes an internal channel interconnecting segments of the proximal internal channel of the jaw member.
 11. The expandable section mill of claim 1, further comprising a top sub having an internal channel in fluid communication with the inner cavity of the body.
 12. An expandable section mill comprising: a body having an outer surface and an inner cavity; a piston disposed within the inner cavity of the body, a lower section of the piston including a first wedge surface and a second wedge surface; a first jaw member pivotally connected to a lower end of the body, the first jaw member including a tapered surface, an internal channel system having an outlet on the tapered surface of the first jaw member, and a pivot surface at an upper end of the first jaw member, wherein the pivot surface is configured to engage the first wedge surface of the piston; a first blade assembly affixed to the tapered surface of the first jaw member, wherein the tapered surface of the first jaw member includes a first wear surface below the first blade assembly; a second jaw member pivotally connected to the lower end of the body, the second jaw member including a tapered surface, an internal channel system having an outlet on the tapered surface of the second jaw member, and a pivot surface at an upper end of the second jaw member, wherein the pivot surface is configured to engage the second wedge surface of the piston; and a second blade assembly affixed to the tapered surface of the second jaw member, wherein the tapered surface of the second jaw member includes a second wear surface below the second blade assembly.
 13. The expandable section mill of claim 12, wherein the piston is moveable within the inner cavity for pivoting the first and second jaw members between a retracted position, in which the first and second blade assemblies are positioned radially inward relative to the outer surface of the body, and an extended position, in which the first and second blade assemblies extend radially outward relative to the outer surface of the body, when the first wedge surface of the piston engages the pivot surface of the first jaw member and the second wedge surface of the piston engages the pivot surface of the second jaw member.
 14. The expandable section mill of claim 13, wherein the piston further includes a first wing extension adjacent to the first wedge surface and a second wing extension adjacent to the second wedge surface, wherein the first wing extension is configured to engage a side surface of the first jaw member for aligning the piston with the first jaw member, and wherein the second wing extension is configured to engage a side surface of the second jaw member for aligning the piston with the second jaw member.
 15. The expandable section mill of claim 13, wherein the outlets of the internal channel systems of the first and second jaw members are disposed adjacent to the first and second blade assemblies on the tapered surfaces for fluid flow through the first and second jaw members to the first and second blade assemblies.
 16. The expandable section mill of claim 15, wherein in the extended position, a first internal channel of the piston is in fluid communication with the internal channel system of the first jaw member and a second internal channel of the piston is in fluid communication with the internal channel system of the second jaw member.
 17. The expandable section mill of claim 16, wherein the piston includes a third internal channel, the first jaw member includes a proximal internal channel extending to an outlet on a rear surface of the first jaw member, and the second jaw member includes a proximal internal channel extending to an outlet on a rear surface of the second jaw member; and wherein in the extended position, the third internal channel of the piston is in fluid communication with the proximal internal channels of the first and second jaw members for fluid flow through the piston and first and second jaw members to the rear surfaces thereof.
 18. A method of cutting a section of a tubular member in a wellbore, comprising the steps of: a) providing an expandable section mill comprising a body having an outer surface and an inner cavity; a piston disposed within the inner cavity of the body, a lower section of the piston including a first wedge surface and a second wedge surface; a first jaw member and a second jaw member each pivotally connected to a lower end of the body, each of the first and second jaw members including a tapered surface, an internal channel system for fluid flow through the first and second jaw members, and a pivot surface at an upper end of the first and second jaw members; a first blade assembly affixed to the tapered surface of the first jaw member; and a second blade assembly affixed to the tapered surface of the second jaw member; wherein the tapered surfaces of the first and second jaw members each includes a wear surface below the first and second blade assemblies; b) lowering the expandable section mill in a retracted position through the tubular member, wherein in the retracted position, the first and second blade assemblies are positioned radially inward relative to the outer surface of the body; c) pivoting the first and second jaw members into an extended position within the tubular member, wherein in the extended position, the first and second blade assemblies extend radially outward relative to the outer surface of the body such that a cutting member of the first blade assembly and a cutting member of the second blade assembly contact an inner surface of the tubular member; and d) rotating the expandable section mill in the extended position in order to cut a section of the tubular member with the cutting members of the first and second blade assemblies.
 19. The method of claim 18, wherein the expandable section mill further includes a top sub having an internal channel in fluid communication with the inner cavity of the body; and wherein step (c) further comprises: i) increasing a pressure of a fluid flowing through the internal channel of the top sub and into the inner cavity of the body to transfer the piston downward; and ii) pivoting the first and second jaw members into the extended position by operatively engaging the pivot surface of the first jaw member with the first wedge surface of the piston and operatively engaging the pivot surface of the second jaw member with the second wedge surface of the piston.
 20. The method of claim 18, further comprising the steps of: e) cutting into the tubular member until the wear surfaces of the first and second jaw members contact the inner surface of the tubular member below the cut section; and f) lowering the expandable section mill while rotating in the extended position to extend the cut section of the tubular member.
 21. The method of claim 18, wherein the tubular member is disposed within a second tubular member in the wellbore, and wherein a cement layer is disposed between an outer surface of the tubular member and an inner surface of the second tubular member, wherein the method further comprises the steps of: e) pivoting the first and second jaw members into the retracted position and lifting the expandable section mill out of the tubular member; f) removing the first and second blade assemblies from the first and second jaw members; g) affixing a first scraper blade assembly to the tapered surface of the first jaw member and affixing a second scraper blade assembly to the tapered surface of the second jaw member; h) lowering the expandable section mill in the retracted position through the tubular member until the first and second jaw members are aligned with the cut section of the tubular member; i) pivoting the first and second jaw members into the extended position such that the first and second scraper blade assemblies contact the cement layer; j) rotating the expandable section mill in the extended position in order to remove a section of the cement layer with the first and second scraper blade assemblies. 